1. Field
The invention relates to sub-systems of automotive radar and methods of manufacturing the same. More particularly, the invention relates to a radar sub-system module which houses a Radio Frequency Integrated Circuit (RFIC) and a waveguide signal transition through which the RFIC may communicate with an antenna array.
2. Description of the Related Art
Automotive radar systems are currently being provided in many automobiles. Over the past few years, automotive radar systems have been used with intelligent cruise control systems to sense and adjust the automobile's speed depending on traffic conditions. Today, automotive radar systems are being used with active safety systems to monitor the surroundings of an automobile for collision avoidance. Current automotive radar systems are divided into long range (for adaptive cruise control and collision warning) and short range (for pre-crash, collision mitigation, parking aid, blind spot detection, etc.). Current systems utilize a radio frequency integrated circuit (RFIC) device in order to process instructions and process communications to and from antenna arrays. A radar unit containing antenna arrays and an RFIC device may be considered a radar sub-system.
RFIC devices are very sensitive to, for example, dust, dirt, and other environmental exposure. Thus, it is desirable to be able to manufacture the RFIC device in a clean environment, such as a clean room, and to house the RFIC device in a sealed environment so that environmental factors (such as dust, dirt, etc.) do not degrade the quality of the RFIC device. This sensitivity creates a need for a sealed environment in which the RFIC device is to be positioned. However, manufacturing an entire radar system in a clean room may be cost prohibitive.
RFIC devices in current vehicular radar systems must be able to pass signals to the antennas. The RFIC device must also be able to communicate with support electronics, such as diodes, capacitors, control integrated circuits, etc. So, in addition to protecting the RFIC device, sub-system packaging must also allow communications between the RFIC device and the antenna circuits and the chip support elements. However, with the RFIC device being positioned in a sealed environment, many problems may arise. For example, communications with both circuits may be difficult (e.g., signal loss may be large, placement of through vias may be difficult, etc.); performance of the RFIC device is reduced; it may not be possible to manufacture and assemble the RFIC device to the sub-system in a clean environment; if the RFIC device is manufactured in a clean room, the entire module may be required to be manufactured in a clean room (increased cost); and any combination of the above problems.
Therefore, a need exists in the art for radar sub-system packaging which allows the RFIC device to be sealed from environmental elements, increases the performance of the RFIC device, allows the RFIC device to effectively communicate with support circuitry as well as antenna circuitry, and allows for less than the entire radar system to be manufactured in a clean room.